vishaltyagi807/mail_service

<explanation>

Below is a step‑by‑step guide on how to translate the mail_service project into a clear, accurate system design diagram. Follow these steps and tailor each to reflect the files and modules you see in the file tree and README.

1. Identify the project type and purpose

- This is a standalone HTTP microservice written in Kotlin using the Ktor framework.

- Its purpose: accept incoming REST calls, serialize/deserialize JSON payloads, render an email template, and send mail via an external SMTP or mail‑API.

2. Analyze the file structure

Top‑level:

• build.gradle.kts, gradle wrapper → build & CI tooling

• src/main/kotlin/dev/varshit → application code

– Application.kt → entry point, installs Ktor engine & plugins

– Routing.kt → HTTP endpoint definitions

– SendRequest.kt → business logic to send mail

– Serialization.kt → data classes + JSON serializers

• src/main/resources → configuration

– application.yaml → service properties (port, SMTP creds)

– logback.xml → logging config

• template.html → static email template

• src/test → unit tests

3. Examine the README for insights

- Features: Routing DSL, Content Negotiation, kotlinx.serialization

- Standard Gradle tasks: build, test, fat‑jar, Docker image

- Server binds to 0.0.0.0:8080

4. Main components & relationships

a. Client

– Any HTTP client (e.g., frontend app, curl)

b. Ktor HTTP Server

– EntryPoint (Application.kt)

– Plugins:

• Routing (Routing.kt)

• ContentNegotiation (Serialization.kt)

– Route handlers invoke SendRequest service

c. Email Service Layer (SendRequest.kt)

– Loads template.html

– Populates template with payload

– Uses Ktor HTTP client or SMTP library to send mail to External Mail API/SMTP

d. Configuration subsystem

– application.yaml feeds server, SMTP settings

e. Logging

– logback.xml configures SLF4J logging of requests & errors

f. External dependencies

– SMTP server or third‑party mail API

5. Architectural patterns/design principles

– Modular separation:

• HTTP layer vs. business‑logic layer vs. external‑integration layer

– Plugin-driven pipeline (Ktor)

– Configuration‑driven behavior

– No database; stateless microservice

6. How to draw the diagram

1. Use rectangles for each component.

2. Color‑code:

• Blue = internal Ktor components

• Orange = configuration & templates

• Green = external dependencies (SMTP/API)

• Gray = build/deploy (Gradle & Docker)

3. Label each box clearly:

– “Ktor Server” container with sub‑boxes:

• Routing DSL

• ContentNegotiation (JSON)

• Application.kt

– “MailService” business logic (SendRequest.kt + template.html)

– “Config” (application.yaml + logback.xml)

– “External Mail API / SMTP”

– “Client”

4. Draw directional arrows to show data flow:

– Client → Ktor Server (HTTP POST /sendMail)

– Ktor Server → MailService (invoke SendRequest)

– MailService → External Mail API

– External Mail API → MailService (response) → Ktor Server → Client (HTTP response)

5. Add notes or callouts for important plugins (kotlinx.serialization).

7. Tailoring guidelines

- Emphasize separation between:

• Transport (HTTP)

• Serialization (JSON<->Kotlin)

• Business logic (template rendering + send)

- Show how the application is packaged (Fat JAR → Docker image) if you want to include deployment.

8. Elements to include in the final diagram

– Component labels (e.g., “Routing.kt”, “SendRequest.kt”)

– Arrowheads to indicate request/response flow

– Color legend for internal vs. external vs. config

– Docker icon (optional) to represent containerization

By following this breakdown, you’ll produce a detailed architecture diagram that maps directly to the project’s files, modules, and runtime behavior without missing any essential components.

</explanation>